NU1085 is a potent poly(ADP-ribose) polymerase (PARP) inhibitors have been developed that potentiate the cytotoxicity of ionizing radiation and anticancer drugs. The biological effects of NU1085 [Ki = 6 nM], in combination with temozolomide (TM) or topotecan (TP) have been studied in 12 human tumor cell lines (lung, colon, ovary, and breast cancer). Cells were treated with increasing concentrations of TM or TP + - NU1085 (10 microM) for 72 h.